M6S1 Peripheral Nervous System

Question 1

Peripheral nervous system

Answer 1

-all of the nerves outside of the brain and spinal cord
-PNS contains spinal and cranial nerves

Can be remembered as everything peripheral to, or outside of the brain and spinal cord
Cranial nerves arise from Brainstem, while spinal nerves arise from spinal cord

Question 2

Divisions of the PNS

Answer 2

*refer to chart in goodnotes

Question 3

Cranial nerves

Answer 3

-emerge in pairs from the brain and brain stem instead of the spinal cord
-12 pairs of cranial nerves
-some only carry sensory information or motor information, while others carry both sensory and motor information
-numbered using Roman numerals and referred to by their number or name
*refer to goodnotes for image

Question 4

CN I - Olfactory Nerve

Answer 4

Information : sensory only
Function:
Sensory - smell
Motor - none

Question 5

CN II - Optic Nerve

Answer 5

Information: sensory only
Function:
Sensory - vision
Motor - none

Question 6

CN III - Oculomotor nerve

Answer 6

Information: motor only
Function:
Sensory - none
Motor - movement of eye (elevation of eye)
* one of the three cranial nerves that sends motor input to the muscles that move eye

Question 7

CN IV - Trochlear Nerve

Answer 7

Information: motor only
Function:
Sensory - none
Motor - movement of eye (as if looking at nose)
* second of the three cranial nerves involved in eye movement

Question 8

CN V - Trigeminal Nerve

Answer 8

Information: sensory and motor
Functions:
Sensory - forehead, eye, upper jaw, lower jaw
Motor - muscles of mastication (so innervate masseter muscle)
*as three divisions, therefore “tri” is logical

Question 9

CN VI - Abducens Nerve

Answer 9

Information: motor only
Function:
Sensory - none
Motor - movement of eye (to abduct eyes, move them laterally)
* the third cranial nerve involved in eye movement

Question 10

CN VII - Facial Nerve

Answer 10

Information: sensory and motor
Functions:
Sensory - taste for anterior 2/3 of tongue
Motor - muscles of facial expression, parasympathetic innervation of tear (aka lakeral) and salivary glands

Question 11

CN VIII - Vestibulocochlear nerve

Answer 11

Information: sensory only
Functions:
Sensory - Equilibrium (vestibular apperatus responsible for that) and hearing (Conkia?, organ responsible for hearing)
Motor - none

Question 12

CN IX - Glossopharyngeal Nerve

Answer 12

Information: sensory and motor
Functions:
Sensory - sensory innervation of the pharynx, taste from posterior 1/3 tongue
Motor - pharynx muscles, parasympathetic intervention of salivary glands
(Glosso=tongue)

Question 13

CN X - Vagus nerve

Answer 13

Information: sensory and motor
Functions:
Sensory - sensory innervation of the larynx
Motor - pharynx and larynx muscles, parasympathetic innervation of the thoracic and abdominal organs (travelling through those cavities)

Question 14

CN XI - (spinal accessory nerve according to video) Accessory Nerve

Answer 14

Information: motor only
Function:
Sensory - none
Motor - trapezius (strug shoulder) and sternocleidomastoid muscles (flex neck and turn head)

Question 15

CN XII - Hypoglossal Nerve

Answer 15

Information: motor only
Function:
Sensory - none
Motor - muscles of the tongue

Question 16

Mnemonic to remember cranial nerves

Answer 16

Once over one Tuesday, the actor finally voted good venue at hogwarts

Question 17

Spinal nerves

Answer 17

-named as such because emerge from spinal cord
-31 pairs
-carry information through the PNS
-formed by union of posterior (sensory) and anterior (motor) roots of spinal cord

Question 18

Classifying spinal nerves

Answer 18

-identified based on letter and number
Letter = region of spinal cord
Number = level
Within cervical region - spinal nerves emerge superior to corresponding vertebrae, Spinal nerve C8 exception , emerging between C7 and T1 (there is no C8 vertebra)
Below the neck - spinal nerves emerge inferior to corresponding vertebra

Question 19

Nerve plexuses

Answer 19

-once spinal nerve exit vertebral column, fibres from anterior roots (motor) come together then redistribute into new networks of nerves (plexuses) that mostly innervate muscles of limb
- each plexus thus contains fibres (collection of axons) from a combination of spinal nerves
-functional important because in case of injury, contribution of multiple spinal nerves into nerve plexus ensures innervation to muscle
-main spinal nerve plexuses in body correspond to the enlargements of spinal cord
-cervical and brachial plexuses correspond to cervical enlargement
-lumbar and sacral plexuses correspond to lumbosacral enlargement
*refer to goodnotes for images